1. Field of the Invention
The present invention is directed generally to the formation of pipe joints and more particularly to the formation of the bell end of a bell and spigot joint.
2. Discussion of the Prior Art
As is well known in the art, the female counterpart member or bell end of a bell and spigot joint, connecting two pipes together includes an elongated bell-shaped sleeve having an inner circumferential groove and a sealing gasket disposed within the groove. One common method of forming the bell end is to insert a core, with a gasket positioned thereon, concentrically into a heated end section of a heat deformable pipe. In this manner, the heated end section deforms around the gasket and ultimately conforms to the contour of the core and gasket to form a bell-shaped sleeve displaying the aforedescribed groove around the sealing gasket.
In many cases, the aforedescribed method requires the utilization of some sort of separate means for carrying the end section of the heat deformable pipe over the gasket during the formation process. Heretofore, one typical way of achieving this has been to position a retainer ring having a tapered side surface on the core and adjacent to the sealing gasket. As the heated end section approaches the gasket, the tapered surface of the retainer ring causes the end section to deform outwardly and over the gasket. The retainer ring, of course, remains within the ultimately formed circumferential groove along with the sealing gasket.
While the utilization of the aforedescribed retainer ring is in certain cases satisfactory for directing the heated end section over the sealing gasket, it does create drawbacks. For example, the retainer ring adds to the cost in producing the bell end of a bell and spigot joint as well as requiring additional tolerance limitations. Further, in many cases, the retainer ring and sealing gasket must be of compatible design for maintaining the latter in place within the inner circumferential groove. Hence, changing from one type of gasket to another would require changing to a different type of retainer ring which can be inconvenient and/or expensive.